Bloody annoying too because police wouldn't even worry about ticketing this guy.
Here I have to disagree. IF the behavior was witnessed by an on duty member than it would mostly certainly result in a ticket. IF you called *555 at the time with the registration details than attempts would be made to locate it than and there. IF you made a formal complaint re the driving at a Police Station than it would be assigned, investigated and (most likely) result in a ticket. IF you just post about it online and don't take any steps to report it than of course no ticket will be issued.
There's several things that Police could have ticked for including Overtaking on the Right while approaching or crossing an Intersection and Level Crossing where exit blocked by stationary traffic (IANAL but a quick search of Legislation.govt.nz/Land Transport (Road User) Rule 2004 gives those two examples).